Tens of millions of people world-wide are living with acquired immunodeficiency syndrome (AIDS), or are infected with the causative agent, human immunodeficiency virus (HIV). In some countries in sub-Saharan Africa, up to one in four adults has contracted the disease. Despite the costs and efforts spent attempting to identify new methods of treatment, a cure for the disease has remained elusive.
Ancient societies have traditionally turned to plants for their health needs. Documented use of herbs to treat illnesses dates back to as early as 2,000 B.C. Recently, individuals have resorted to nature as remedies and medicines for the treatment of modern illnesses have been derived from plants, such as for example, treatment of HIV and other infectious diseases.
For example, U.S. Pat. No. 5,178,865 discloses an experimental treatment with 56 herbs, and reports that 10 of the 56 herbs exhibit anti-HIV activity in in vitro experiments. The 10 herbs include: Coptis chineusis, Ligusticum wallichii, Ilicium eanclolatum, Isatis tinctoria, Salvia miltiorrhiza, Erycibe obtusifolia, Acanthopanax graciliatylus, Bostaurus domesticus, Inula helenium and Lonicera japonica. Both Bostaurus domesticus and Lonicera japonica are further described to be able to combine with Scutellaria baicaleusis to exhibit anti-HIV activity.
U.S. Pat. No. 5,837,257 discloses Chinese herbal medicines that exhibit in vitro antiviral activity against murine leukemia virus and HIV and for treatment of animals and humans infected with HIV. In one of the preferred embodiments, the Chinese herbal medicines contain hedyotis, Scutellarial barbatae herba, Lonicera flos, Prunellae spica and Solani harba. 
U.S. Pat. No. 5,989,556 discloses various herbal compositions for treating viral infections which have shown in vitro antiviral activities against HIV. A first herbal composition contains Aeginetiae herba, Blechni rhizoma, Lespedezae herba, Polygoni cuspidati rhizoma, Forsythiae fructus, and Ligustri fructus. A second herbal composition contains Cirsii rhizoma and radix, Breeae radix, Baphicacanthis rhizoma and radix, Phellodendri cortex, and Bletillae tuber. A third herbal composition disclosed in the patent includes Aeginetiae Herba, Lonicerae, Flos, Prunellae spica and Lespedezal herba. 
U.S. Pat. No. 6,696,094 discloses an herbal pharmaceutical composition for treating HIV/AIDS. The pharmaceutical composition contains 14 ingredients, including: diffuse hedyotis, bistort rhizome, giant knotweed rhizome, Asiatic moonseed rhizome, baical skullcap root, Bovine biliary powder, milkvetch root, barbary wolfberry fruit, sanqi, figwort root, Chinese magnoliavine fruit, turmeric root-tuber, hawthorn fruit and Chinese angelica. Procedures are provided for the preparation of an “HIVCIDE condensate”, which can be formulated as an injectible solution or as capsules. Results indicate that subjects injected with HIVCIDE solution showed no symptoms of acute or chronic toxicity. Further, the HIVCIDE injection solution was effective in inhibiting pathological changes in cells caused by HIV-1 in vitro. In a third experiment, the HIVCIDE injection solution was effective in reducing symptoms of HIV-infected subjects in a treatment regime together with administration of HIVCIDE capsules. HIV-positive subjects did not show adverse reactions to HIVCIDE injection solution. It was further reported three out of four subjects showed improvement in fatigue after treatment with HIVCIDE, and that HIV viral load studies indicated that all subjects demonstrated reduced HIV viral loads.
U.S. Pat. No. 6,455,078 discloses a medical herbal composition for treating liver diseases and HIV. The composition contains 15 ingredients, which includes diffuse hedyotis, bistort rhizome giant knotweed rhizome, Asiatic moonseed rhizome, baical skullcap root, bovine biliary powder, milkvetch root, barbary wolfberry fruit, sanqi, red ginseng, figwort root, Chinese magnoliavine fruit, turmeric root-tuber, hawthorn fruit and Chinese angelica. Among the 15 ingredients, diffuse hedyotis, bistort rhizome, giant knotweed rhizome, and Chinese magnoliavine fruit are cited as being necessary to contribute to the efficacy of the pharmaceutical composition.
In U.S. Pat. No. 5,366,725, an extract from the seeds of Aeginetia indica was prepared which exhibited excellent carcinostatic effects and possesses interleukin-2 and interferon-gamma-inducing properties. The extract is believed to be a macromolecular polysaccharide, which may or may not contain Lipid A binding with protein depending on whether the extraction is conducted using butanol or phenol. The extracted substance is soluble in water, insoluble in n-butanol, and has a molecular weight ranging from 100,000 to 200,000 Daltons.
U.S. Pat. No. 5,411,733 to Hozumi, et al., discloses a variety of plant extracts for use as anti-herpes viral, anti-polioviral, anti-varicella-zoster virus, anti-measles virus, anti-cytomegalovirus (CMV), and anti-DNA and anti-RNA virus agents.
U.S. Pat. No. 5,178,865 discloses the anti-HIV activity in vitro of a variety of herbs known in China to exhibit anti-viral activity. Water extractions of the mixtures, treatment with ethanol for precipitation and charcoal adsorption are disclosed for the preparation for the anti-HIV-active composition.
Two lignans, phyllamycin B and retrojusticiden B, have been reported to have an inhibitory effect on HIV-1 reverse transcriptase activity. The lignans are isolated from Phyllanthus myrtifolius Moon, a plant widely grown in Southern China. See, for example, Chang, et al., Antiviral Research, 27 (4), 367-374 (1995).
A mixture of aqueous extracts of Lonicera japonica flower buds, Forsythia suspensa fruits, and Scutellaria baicalensis rootbark have been shown to have antibacterial and antiviral properties. Subjects with severe respiratory disease treated with the mixture responded as well as a control group on standard antibiotic therapy. See Houghton, et al., Phytother. Res. 7(5), 384-386 (1993).
A water extract of Prunella vulgaris was reported to have anti-HIVB activity when administered in combination with zidovudine (AZT) and didanosine (dd1). Only a slight additive effect was observed for the administration of an extract of Prunella vulgaris and zalcitabine (ddC). See John, et al., Abstr. Gen. Meet. Am. Sc. Microbiol, 94, 481 (1994).
Yamasaki et al. have reported the in vitro evaluation of 204 crude drugs commonly used in Japan for anti-HIV-1 activity and studies indicate that hot water extracts of Lithospermum erythrorhizon (root) and Prunella vulgaris (spike) showed strong in vitro anti HIV-1 activity with an IC.sub.100 of 16 mu.g/mL. See Yamasaki, et al., Yakugaku Zasshi 113(11), 818-824 (1993).
Yao et al. have reported that water extracts of dried Prunella vulgaris (whole plant) were active in vitro for inhibiting HIV-1 replication, and showed relatively low cytotoxicity to MT-4 cells. The extract also demonstrated activity in the inhibition of reverse transcriptase. The active factor was purified and identified as anionic with a molecular weight of approximately 10,000 Daltons. This active component may be the same as the prunellin, as described by Tabba. See Tabba, et al., Antiviral Research 11, 263-273 (1989). The purified extract inhibited HIV-1 replication in the lymphoid cell line MT-4, in the monocytoid cell line U937, and in peripheral blood mononuclear cells (PBMC) at effective concentrations of 6.3 and 12.5 mu.g/mL, respectively. Pretreatment of uninfected cells with the extract prior to viral exposure did not prevent HIV-1 infection upon subsequent exposure to the virus. Preincubation with the purified extract decreased HIV-1 infectiousness. The purified extract also blocked cell-to-cell transmission of HIV-1, prevented syncytium formation, and interfered with the ability of both HIV-1 and purified gp 120 to bind to CD4. PGR (polymerase chain reaction) analysis confirmed the absence of HIV-1 proviral DNA in cells exposed to virus in the presence of the extract, suggesting that the purified extract antagonized HIV-1 infection of susceptible cells by preventing viral attachment to the CD4 receptor. See Yao, et al., Virology 187(1), 56-62 (1992).
Tabba, et al. isolated and partially characterized prunellin, a compound exhibiting anti-HIV properties, from aqueous extracts of Prunella vulgaris, a Chinese herb. Prunellin was identified as a carbohydrate (a partially sulfated polysaccharide) with an minimum inhibition concentration of 2.2 μg/mL against HIV-1 in vitro. It was identified as having a molecular weight of about 10,000 Dalton. See Tabba, et al., Antiviral Research 11, 263-273 (1989).
Antiviral agents have been isolated from Syzygium aromatica, Sapium sebiferum (Chinese tallow tree leaves), Scutellaria baicalensis, and Scutellaria rivularis. Eugeniin, (a tannin isolated from Syzygium aromatica), and methyl gallate, (isolated from Sapium sebiferum), exhibited anti-herpes simplex virus (HSV-2) activity in vitro. Plant flavonoids, such as 5,7,4-truhydroxyflavone, extracted from the whole herb Scutellaria rivularis, were reported to have anti-influenza virus activity. See Hozumi, et al., U.S. Pat. No. 5,411,733; Takechi, et al., Planta Medica 42, 69-74 (1981); Kane, et al., Bioscience Report 8, 85-94 (1988); and Nagai, et al., Chem. Pharm Bull. 38(5), 1329-1332 (1990).
Ethiopian medicinal plants known for treatment of a variety of ailments were screened for activity against HIV-1 and HIV-2, as reported by Asres, et al. Extracts from Bersama abyssinica root bark, Combretum paniculatum leaves, Dodonaea angustfolia leaves, and Ximenia Americana stem bark each displayed anti-viral activity at concentrations that were non-toxic to MT-4 cells. Anti-viral activity of the extracts is noted to be more effective against HIV-1 than HIV-2. See Asres, et al., Phytother. Res., 15, 62-69 (2001).
Selected plants used in traditional Rwandan medicine for treatment of infections and/or rheumatoid diseases were investigated for antiviral activity in vitro against HIV-1. See Cos, et al., Phytomedicine 9, 62-68 (2002). Of 38 plant extracts tested, extracts from the leaves of Aspilia pluriseta and Rumex bequaertii had the highest antiviral activities.